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Lorazepam, sold under the brand name Ativan among others, is a benzodiazepine medication often used to treat anxiety disorders.〔(USA-NIH Medline Plus information )〕 Lorazepam reduces anxiety, interferes with new memory formation, reduces agitation, induces sleep, treats seizures, treats nausea and vomiting, and relaxes muscles.〔 Lorazepam is used for the short-term treatment of anxiety, insomnia, acute seizures including status epilepticus, and sedation of hospitalized patients, as well as sedation of aggressive patients.〔〔〔〔 Due to tolerance and dependence, lorazepam is recommended for short-term use, up to two to four weeks only. Among benzodiazepines, lorazepam has possible physical addiction potential.〔 Lorazepam also has misuse potential; the main types of misuse are for recreational purposes.〔 Long-term effects of benzodiazepines include tolerance, dependence, benzodiazepine withdrawal syndrome, and cognitive impairments which may not completely reverse after stopping treatment. In most people cognitive impairment is not severe. Withdrawal symptoms can range from anxiety and insomnia to seizures and psychosis. Adverse effects, including inability to form new memories, depression, and paradoxical effects, such as excitement or worsening of seizures, may occur. Children and the elderly are more sensitive to the adverse effects of benzodiazepines. Lorazepam impairs body balance and standing steadiness and is associated with falls and hip fractures in the elderly.〔 Lorazepam was initially patented in 1963 and went on sale in the United States in 1977. It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system. ==Medical uses== Lorazepam has anxiety-reducing effects and its best-known indication is the short-term management of severe anxiety; the FDA advises against use of benzodiazepines such as lorazepam for longer than four weeks.〔 It is fast acting, and useful in treating fast onset panic anxiety. Lorazepam can effectively reduce agitation and induce sleep, and the duration of clinical effects from a single dose makes it an appropriate choice for the short-term treatment of insomnia, especially in the presence of severe anxiety or night terrors. It has a fairly short duration of action.〔Venable and Aschenbrenner 2009〕 Withdrawal symptoms, including rebound insomnia and rebound anxiety, may occur after only seven days' administration of lorazepam. Lorazepam is sometimes used for individuals receiving mechanical ventilation. However, in critically ill patients, propofol has been found to be superior to lorazepam both in effectiveness and overall cost; as a result, the use of propofol for this indication is now encouraged, whereas the use of lorazepam is discouraged. Its relative effectiveness in preventing new memory formation,〔 along with its ability to reduce agitation and anxiety makes lorazepam useful as premedication. It is given before a general anesthetic to reduce the amount of anesthetic agent required, or before unpleasant awake procedures, such as in dentistry or endoscopies, to reduce anxiety, to increase compliance, and to induce amnesia for the procedure. Oral lorazepam is given 90 to 120 minutes before procedures, and intravenous lorazepam as late as 10 minutes before procedures. Lorazepam is sometimes used as an alternative to midazolam in palliative sedation. In intensive care units lorazepam is sometimes used to produce anxiolysis, hypnosis, and amnesia. Intravenous diazepam or lorazepam are first-line treatments for convulsive status epilepticus.〔 Lorazepam is more effective than diazepam in the treatment of status epilepticus. However, phenobarbital has a superior success rate compared to lorazepam and other drugs, at least in the elderly. Its marked anticonvulsant properties, and its pharmacokinetic profile, make intravenous lorazepam a reliable agent for stopping acute seizures, but it has relatively prolonged sedation after-effects. Oral lorazepam, and other benzodiazepines, have a role in long-term prophylactic treatment of resistant forms of petit mal epilepsy, but not as first-line therapies, mainly because of the development of tolerance to their effects. Lorazepam's anticonvulsant and CNS depressant properties are useful for the treatment and prevention of alcohol withdrawal syndrome. In this setting, impaired liver function is not a hazard with lorazepam, since lorazepam does not require oxidation, hepatic or otherwise, for its metabolism.〔 Lorazepam is sometimes used as an alternative to haloperidol when there is the need for rapid sedation of violent or agitated individuals, but haloperidol plus promethazine is preferred due to better effectiveness and due to lorazepam's adverse effects on respiratory function. However, adverse effects such as behavioral disinhibition may make benzodiazepines inappropriate for some acutely psychotic patients. Acute delirium is sometimes treated with lorazepam, but as it can cause paradoxical effects, it is preferably given together with haloperidol. Lorazepam is absorbed relatively slowly if given intramuscularly, a common route in restraint situations. Catatonia with inability to speak is responsive to lorazepam. Symptoms may recur and treatment for some days may be necessary. Catatonia due to abrupt or overly rapid withdrawal from benzodiazepines, as part of the benzodiazepine withdrawal syndrome, should also respond to lorazepam treatment. As lorazepam can have paradoxical effects, haloperidol is sometimes given at the same time.〔 It is sometimes used in chemotherapy in addition to medications used to treat nausea and vomiting, i.e. nausea and vomiting caused or worsened by psychological sensitization to the thought of being sick. It is also used as adjunct therapy for cyclic vomiting syndrome. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「lorazepam」の詳細全文を読む スポンサード リンク
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